<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>Drandarov K</dc:creator>
  <dc:creator>Schubiger PA</dc:creator>
  <dc:creator>Westera G</dc:creator>
  <dc:date>2006</dc:date>
  <dc:description xmlns:ns0="xml" ns0:lang="en">The first purely chemical method for automated no-carrier-added synthesis of [1-(11)C]-labeled d(R)- and l(S)-2-hydroxypropanoic acid (lactic acid) was developed for experimental neurophysiology studies and position emission tomography (PET) diagnosis. Starting from sodium 1-hydroxyethanesulfonate and [(11)C]HCN (trapped as [(11)C]KCN) the intermediate dl-(R,S)-[1-(11)C]-2-hydroxypropanenitrile was prepared. Its rapid acid hydrolysis gave dl-(R,S)-[1-(11)C]lactic acid, which was isolated by preparative reversed phase HPLC and automatically injected on a second preparative C(18) HPLC column coated with a chiral selector, where both [1-(11)C]lactic acid enantiomers were separated by chiral ligand-exchange chromatography. Two novel chiral selectors for HPLC enantiomeric separation of alpha-hydroxy acids, namely d(R)- or l(S)-2-amino-3-methyl-3-(5-phenylpentylsulfanyl)-butanoic acid were utilized for the preparative HPLC separation of the [1-(11)C]lactic acid enantiomers. The preparation of the selectors and the coating procedure for the manufacturing of the preparative chiral HPLC columns are described. A highly efficient trap for [(11)C]HCN is presented. The whole radiosynthesis is automated, takes about 45 min and leads to more than 80% decay corrected overall radiochemical yield of each enantiomer (up to 2.5 GBq) with over 99% radiochemical, chemical and enantiomeric purity. The specific activity at the end of the synthesis is about 400 GBq/micromol.</dc:description>
  <dc:identifier>https://sonar.ch/global/documents/47281</dc:identifier>
  <dc:language>eng</dc:language>
  <dc:relation>info:eu-repo/semantics/altIdentifier/doi/10.1016/j.apradiso.2006.05.013</dc:relation>
  <dc:relation>info:eu-repo/semantics/altIdentifier/pmid/16854588</dc:relation>
  <dc:source>Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine. - 2006</dc:source>
  <dc:subject xmlns:ns1="xml" ns1:lang="en">Carbon Radioisotopes</dc:subject>
  <dc:subject xmlns:ns2="xml" ns2:lang="en">Chromatography, High Pressure Liquid</dc:subject>
  <dc:subject xmlns:ns3="xml" ns3:lang="en">Lactic Acid</dc:subject>
  <dc:subject xmlns:ns4="xml" ns4:lang="en">Radiochemistry</dc:subject>
  <dc:subject xmlns:ns5="xml" ns5:lang="en">Stereoisomerism</dc:subject>
  <dc:title xmlns:ns6="xml" ns6:lang="en">Automated no-carrier-added synthesis of [1-11C]-labeled D- and L-enantiomers of lactic acid.</dc:title>
  <dc:type>http://purl.org/coar/resource_type/c_6501</dc:type>
</oai_dc:dc>